Of course it does - it´s simple geometry - when a prime lens is extended
while focusing close the focal length increases. If it were an internal
focusing zoom, it would focus close by decreasing the focal length - and
then you would be complaining that it does not have the indicated focal
length in the near range.
Those are the options, you choose.
About the dust - what magnification ratios do you use - I´d say that in
order to really show in images the dust inside the lens the magnification
must be rather extreme.
All the best!
Raimo K
Personal photography homepage at:
http://www.uusikaupunki.fi/~raikorho
----- Original Message -----
From: "Tim Øsleby" <[EMAIL PROTECTED]>
To: <pentax-discuss@pdml.net>
Sent: Friday, October 28, 2005 10:32 PM
Subject: RE: My new Macro - a lemon.
When saying zoom I mean that the angle of view changes. Going from open to
near closed, the angle narrows. I find it strange, very strange. Not much,
but visible. It makes me suspicious.
I have made a rough test. The thing is that I having trouble finding time
to
do it more properly.
Tim
Mostly harmless (just plain Norwegian)
Never underestimate the power of stupidity in large crowds
(Very freely after Arthur C. Clarke, or some other clever guy)
-----Original Message-----
From: Boris Liberman [mailto:[EMAIL PROTECTED]
Sent: 28. oktober 2005 19:48
To: pentax-discuss@pdml.net
Subject: Re: My new Macro - a lemon.
Hi!
> The FA50/2,8 came today. Very disappointing.
>
> First, there is dust in it. Visible from 5,6 and up.
> Second, it behaves strangely when stepping up or down. It zooms out
> when
> going down at close range.
> Third, the AF is extremely poor. I could live with that, but on top of
the
> dust and the tendency to zoom... No way.
>
> I'll give it a second try, because it was cheap. But most likely I'll
send
> the seller a mail telling him what I think about it.
Tim, unless I misunderstand what you meant by zooming, looking here may
soften your concern somewhat:
http://kmp.bdimitrov.de/lenses/primes/normal/FA50f2.8-Macro.html
I think your macro lens should actually "zoom" when going to close
range... Tamron 90/2.5 of mine does something similar...
Perhaps making a test shoot on various apertures and various distances
may be in order.
Boris
